title: Calcium hydroxide inactivates lipoteichoic acid from Enterococcus faecalis.
abstract: Calcium hydroxide is a widely used endodontic medicament for eliminating viable bacteria and inactivating virulence factors. Enterococcus faecalis, a pathogenic gram-positive bacterium, has been associated with refractory apical periodontitis. Because lipoteichoic acid (LTA) is a major virulence factor of gram-positive bacteria, we examined whether calcium hydroxide could detoxify LTA from E. faecalis. An enzyme-linked immunosorbent assay showed that calcium hydroxide-killed E. faecalis was less potent than heat-killed bacteria in stimulating the release of tumor necrosis factor-alpha by a murine macrophage line, RAW 264.7 (P < 0.05). Pretreatment of LTA with calcium hydroxide remarkably abrogated the ability of LTA to induce the release of tumor necrosis factor-alpha (P < 0.05). Furthermore, calcium hydroxide-treated LTA was not able to stimulate Toll-like receptor 2, which recognizes functionally intact LTA. These results suggest that calcium hydroxide could detoxify LTA, resulting in attenuation of the inflammatory responses to E. faecalis and its LTA.
authors.affiliation: Department of Oral Microbiology and Immunology, Dental Research Institute, and BK21 Program, School of Dentistry, Seoul National University.
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Baik
authors.affiliation: Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University.
authors.forename: Kee-Yeon
authors.initials: KY
authors.lastname: Kum
authors.affiliation: School of Agricultural Biotechnology, Seoul National University; Research Institute for Agriculture and Life Sciences, Seoul National University.
authors.forename: Cheol-Heui
authors.initials: CH
authors.lastname: Yun
authors.affiliation: Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University.
authors.forename: Jin-Kyung
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Department of Life Science, Chung-Ang University.
authors.forename: Kangseok
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Oral Microbiology and Immunology, Dental Research Institute, and BK21 Program, School of Dentistry, Seoul National University.
authors.forename: Kack Kyun
authors.initials: KK
authors.lastname: Kim
authors.affiliation: Department of Oral Microbiology and Immunology, Dental Research Institute, and BK21 Program, School of Dentistry, Seoul National University; International Vaccine Institute, Seoul, Republic of Korea. Electronic address: shhan-mi@snu.ac.kr.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Han
mesh_terms: D000818:Animals; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002460:Cell Line; D013293:Enterococcus faecalis / Q000737:chemistry / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors*; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D012388:Root Canal Irrigants / Q000494:pharmacology*; D013682:Teichoic Acids / Q000037:antagonists & inhibitors*; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D037521:Virulence Factors / Q000037:antagonists & inhibitors
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D012388:Root Canal Irrigants; D013682:Teichoic Acids; D051195:Toll-Like Receptor 2; D014409:Tumor Necrosis Factor-alpha; D037521:Virulence Factors; C009900:lipoteichoic acid; D002126:Calcium Hydroxide